\chapter{Introduction}

% (5 pages) Introduce the game, explaining what it does. Assume that the
% marking panel will not have played the game
%
% Gamemodes
%   - game mode
%   - quickplay mode
%
% Gameplay
%   - pick-ups
%   - score collectables
%   - time constraints
%   - lives
%   - Moving platforms
%   - teleports
%   - Endzones
%   - ghosting
%
% Scoring
%   - bonuses
%   - high scores
%
% Replays
%   - recorded high score runs
%   - playback speed

\textit{I am Orb} is a single player arcade-style 3D game for the motion pod
platform. It combines puzzle-solving elements with demanding obstacle-ridden
courses to provide a fun, absorbing and addictive gameplay. The aim of the game
is simple: to guide an orb from the initial starting point, all the way through
a level, to an end-zone within a specified time limit whilst accumulating
collectable objects and achieving as high a score as possible. The player must
direct the orb over and around difficult obstacles such as moving platforms and
tight corners in order to progress through a level, making sure to not fall off
at any point. The motion pod (pod) provides the player with realistic simulation
of different movements, such as collisions of the orb with obstacles and changes
in the direction of gravity, and an immersive audio and visual environment.

The main premise of \textit{I am Orb's} gameplay is that the player is not
directly in control of the orb itself. Instead, they have control of the pitch
and roll of the level environment. For example, to make the orb move forwards
the whole level must be pitched down in relation to the player. At first,
such an interface might not seem intuitive, but it can quickly be mastered to
gain precise orb-control.

The game incorporates a range of pick-ups into the levels that can arm the player
with valuable bonuses or inflict detrimental effects upon them. Often pick-ups
are vital to the completion of a level in some way, or may just provide a little
extra time to collect some more points. Players must work to avoid negative
pick-ups; for instance, an inverting pick-up may be placed before a particularly
difficult section, having the effect of inverting the player's input so that
left becomes right and so on. The player may also need to travel through
teleports to reach parts of the levels they could not otherwise. Similarly,
moving objects could be the only way to cross some large gaps.

The gameplay has an arcade-style interface where the emphasis is to complete a
variety of different levels, each with just several seconds or minutes available
to finish, whilst trying to gain a high scoring run for the level. With a large
enough score, a player can add his or her name to a board of high scores. Their
score is then presented to future players as a challenge to claim their own
position on the high score board.

\section{Game Modes}

The game offers two main modes of play; `game mode' and `quickplay'. The game
mode starts from level one, and after each stage is successfully completed,
progresses the player to the next level. There are a fixed number of levels and
after the last one has been completed, the player will have completed the game.
When a level is completed in game mode the next level is `unlocked' so that it
is available to play in the quickplay mode. The idea of quickplay is for the
player to play any unlocked level so that they can either practice to aid
progression in the game mode or to try and achieve a position on the high score
board. A game mode high score can be achieved if all the levels are completed
successfully. The player not only receives a rating based on their total score
but can also enter the `Balls of Fame' if their score is good enough.

\section{Gameplay Elements}

\subsection{Pick-ups}

The levels contain two types of collectable elements for the player to pick-up.
The first set are most common and add a set number of points to a player's
score. There are three different types of these where each one carries a
different score bonus. They all have the same shape but are differentiated by
colour (Figure \ref{collectables}). The second type are power-ups which have associated
effects when they are obtained. There are six in total (Figure \ref{power-ups}),
three with positive effects to the player and three with negative effects.

% Pictures of all the score pick-ups
\begin{figure}[ht]
\begin{center}
\includegraphics[scale=0.6]{images/collectables.png}
\end{center}
\caption{Collectable pick-ups}
\label{collectables}
\end{figure}

% Pictures of all the pick-ups and the overlay icons
\begin{figure}[ht]
\begin{center}
\includegraphics[scale=0.6]{images/pickups.png}
\end{center}
\caption{Powerup pick-ups}
\label{power-ups}
\end{figure}

The positive power-up effects include: an extra life, useful in the game mode
and worth points in quickplay; some extra time to complete the current level;
and increasing the size of the orb, especially useful to cross wide gaps. The
negative power-up effects include: hyper-sensitive controls, making it more
difficult to make precise movements; inverted control axis, to make it harder
for the player to control the direction of the orb; and increased gravity
strength, having the effect of making the orb roll faster and giving the player
less time to react.

Apart from the life and time bonuses, all of the effects have a set duration,
which changes depending on the level, after which their influence on the player
is removed. When an effect from one of the power-ups is active, an associated
icon is displayed in the bottom right hand corner of the player's screen. All of
the power-ups look similar to the points pick-ups in the game except that they are
white. They also all have different icons in the middle to differentiate between
each one. All positive power-ups have green icons whilst the negative icons are red.

Unlike the normal score pick-ups, these power-ups can have a direct
effect on a player's progression through a level. Sometimes, it may be necessary
to collect certain power-ups in order to complete a level. For example, the orb
may only be able to traverse certain sections of the level when the increased
size power-up is active.

\subsection{Life and Time Constraints}

In the game mode, two main constraints are imposed on the player. Firstly they
must complete a level in a specified time. The time that they have remaining is
displayed with a countdown timer at the top of the screen. The second constraint
is the number of lives that a player has. If the player either runs out of time, or falls off
of a part of the level, then a life is deducted and they must start again with
their score reset. A player can only restart a level if they have lives left, if
they don't then the game is over. Any life pick-ups collected will contribute
one extra life. The number of extra lives a player has is indicated by a number
next to the life icon in the top left hand corner of the screen. A time pick-up
adds a customisable amount of time, defined as part of the level, to the current
amount of time that is left.

In quickplay mode, the player has only the constraint of time as the level can
be replayed as many times as he or she wishes. If an extra life is obtained 
while playing quickplay, the player will still receive bonus points when the level
is completed.

\subsection{Scoring}

The scoring for a level in both game and quickplay modes is equivalent. This is
so that scores gained while playing a level in quickplay can be fairly
compared to those achieved from playing game mode. They remain equivalent by
the collection of extra lives contributing to a score bonus, and the level
score being reset when a player falls out or runs out of time.

At the end of a successfully completed level, the player is awarded a score
composed of the points collected, bonus from extra lives collected and a bonus
for the extra time that was not used. In both game mode and quickplay, if the
score is high enough the player can add their score along with their name to the
high scores board. In game mode the players score is added to a running total.
If every level in the game mode is completed, then there will be a possibility
to add a high score to the "Balls of Fame".


\section{Interactive Level Elements}

%Each level will contain `dynamic' or `interactive' elements to obstruct or aid
%the orb's progress.

\subsection{Moving Objects}

Moving objects are quite simply parts of the level that move around a
predetermined path. These moving features manifest themselves in two main ways.
The first as platforms which can vary in size and shape and can move at varying
speeds (Figure \ref{moving_objects}). In most cases platforms will not move
until the orb is on them, otherwise they will follow their movement path
regardless of where the orb is in the level. Secondly, they feature as moving
obstacles that the orb has to navigate around. The images below show some moving
objects in action.

%Pictures of moving platforms, and as obstacles
\begin{figure}[ht]
\begin{center}
\includegraphics[scale=0.42]{images/platforms.png}
\end{center}
\caption{Moving platforms}
\label{moving_objects}
\end{figure}

Some levels also contain movable objects. These are different to moving objects
in that they can be pushed around by the orb and have no pre-determined path.

\subsection{Teleports}

Teleports enable the orb to travel between two parts of a level instantaneously.
Teleports are always placed in pairs with no restriction on the direction of
travel between them. When the orb enters a teleport it shrinks in size and
disappears in a flash of colours (Figure \ref{teleports}) and is ejected in the
partner teleport where it is restored to its normal size. Teleports preserve the
orbs' speed but alter its direction of travel so that on exit you can continue
in the correct direction. In some levels you may need to enter a teleport with
sufficient speed to clear an obstacle on the other side.

%Pictures of teleports
\begin{figure}[ht]
\begin{center}
\includegraphics[scale=0.5]{images/teleports.png}
\end{center}
\caption{Teleports}
\label{teleports}
\end{figure}

\subsection{Endzones}

On contact with an end-zone, the level is immediately completed. Endzones are
identified by a stream of particles emitted from their base (Figure
\ref{end-zone}).

%Pictures of end-zone
\begin{figure}[ht]
\begin{center}
\includegraphics[scale=0.2]{images/endzone.png}
\end{center}
\caption{Endzones}
\label{end-zone}
\end{figure}

\section{Replays and High Score Ghosting}

After completion of a level in game or quickplay mode, the player has the option
to watch a play-back of their last run of a level. If a high score is achieved
and added to the board then the replay is automatically saved with this entry. The replay then
becomes available for any player to watch when viewing the high score boards in
the main game menu. This system enables players to learn the secrets of others
who have gained incredible scores, as well as learning from their mistakes.

Coupled with the replay functionality, the player also has the option in each
level to play against a ghost. This is activated by selected Ghost Mode on the 
loading screen. The ghost will replay the highest scoring run for that level (if there
is one) so that the player will be able to see exactly how the high score was 
achieved and race against it to try and beat it. This adds an extra experience 
for the player and a sense of competition during the gameplay. Figure \ref{ghost-mode}
shows ghost mode in action.

\begin{figure}[ht]
\begin{center}
\includegraphics[scale=0.2]{images/ghost}
\end{center}
\caption{Ghost mode}
\label{ghost-mode}
\end{figure}

\section{The Menu Interface}

% also mention buttons to press in-game?
% and buttons you can press in menus?

\textit{I am Orb} has an elegant and simple menu interface, providing intuitive
navigation of the game's features. The menus are broadly divided into two
sections; main menu and in-game. The main menu presents options to start a new
game, start a quickplay game, view all of the high scores, change preferences and
to quit.

In the high score menu you are able to browse through the high scores of each
level that has been unlocked in the game. Each high score board contains five
scores, with a name and an icon that can be clicked to watch the replay of the
run. The options menu is a single screen where settings for the player
perspective, resolution, default input device, selection of the in-game skies
(random or by time of day), anti-aliasing level, full screen mode, and volume
for sound effects and background music. This options menu is also available from
the in-game pause menu.

% can you try again in game mode?
% need to clarify about how you do this in the pod.
Starting a new game will take the player to a loading screen for the first level
where they will be presented with an image of the level, the time available to
complete it, the highest score that has been achieved and the option to enable a
ghost of the high score. When the level has finished loading buttons will appear
to either play or quit. On successful completion of a level a `level complete'
screen will be displayed, where the player is presented with a breakdown of
their total score and the high scores for the level. Their score breakdown
includes collected points, bonuses achieved, the total level score and the total
game score so far. If they obtained a new high score they will be able to enter
their name to add to the board. The player can then click a button to progress
to the next level. On failure of a level, the high scores will be displayed but a
high score cannot be added even if their score exceeded the requirement. From
this point they will be able to click to try again and start from scratch or to
quit. Successfully completing all of the levels in this mode will conclude in a
`completed' screen, similar to a level complete screen, but presenting the
overall high scores for the game.

Starting a quickplay game will take the player to a level select menu for them
to choose from any of the unlocked levels available. Selecting a level here will
move to the loading screen just as with game mode. The outcome of a quickplay
game can only be success or failure, the player is presented with the according
menu. Again, a player is only eligible for a high score if the level was
completed successfully. For both the game and quickplay in-game menus, replays
of the player's runs are played behind the menu's semi-transparent background of
the post-play screens. A button is available for the player to watch the replay
properly. Whilst playing a game, the player will have access to the pause
menu by pressing the 'p' or 'escape' buttons. From this menu you can adjust the
game options, quit or resume.

\section{In-game Overlays}

When a player is actually playing the game, a simple overlay (Figure \ref{HUD})
is presented to display three important pieces of information. These are the 
remaining lives, the remaining time, and current score. This is displayed at the
top of the screen right to left respectively. If the `s' key is pressed while
playing the values for the current frame rate and number of triangles rendered
are also displayed in the bottom left hand corner of the screen.

%Pictures of HUD
\begin{figure}[ht]
\begin{center}
\includegraphics[scale=0.35]{images/hud.png}
\end{center}
\caption{In-game overlay}
\label{HUD}
\end{figure}

\section{The Motion Pod}

The motion pod gives the player a rich and immersive interaction with the game
by changing the player's sense of orientation and gravity. Every tilt of the
level and every motion of the orb is realistically simulated by the pod to make
the player really engage with the gameplay. Effects such as accelerating down a
slope, or a head on collision with a wall are all simulated. The player is also
subject to an impressive visual experience with the three monitors in the pod to
give a panoramic view of the game.
